The invention relates to a lock cylinder having a housing and mounted rotatably therein a lock member, and having a driving shaft for driving the lock member.
A lock cylinder of the kind in question is known from DE 42 34 321 A1, the lock cylinder having an optical fibre led right through the driving shaft. An optical fibre branch directed transversely to the optical fibre leads at the end face of the driving shaft to an evaluation unit co-operating with a magnet coil. The optical fibre is rotatable together with the driving shaft.